Device for Transmitting Torque from a Drill to a Drill Bit

ABSTRACT

A device for transmitting a torque from a drill to a drill bit includes a shank and a tool fitting. The shank has a first outer conical region, a groove region, and a second outer conical region and has first longitudinal grooves and second longitudinal grooves. The tool fitting has a basic body which has first outer rotary driving grooves, an intermediate element which has first inner rotary drivers, second inner rotary drivers, and first outer rotary drivers, and has a locking device. In the connected state, the first inner rotary drivers engage in the first longitudinal grooves, the second inner rotary drivers engage in the second longitudinal grooves, and the first outer rotary drivers engage in the first outer rotary driving grooves.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a device for transmitting a torque from a drill to a drill bit.

EP 1 211 005 B1 discloses a known device for transmitting torque from a drill to a drill bit. The device for transmitting torque is arranged between the drill and the drill bit and transmits the torque, which is produced by a drill motor of the drill, to the drill bit. The device for transmitting torque comprises a tool fitting which is permanently connected to the drill or is connected to the drill via a releasable connection, and a shank which is permanently connected to the drill bit or is connected to the drill bit via a releasable connection.

The shank is constructed in a sleeve-shaped manner from a first outer conical region, a groove region, a second outer conical region and a cylinder region and comprises a plurality of first longitudinal grooves extending over the first outer conical region, the groove region, the second outer conical region and the cylinder region, and a plurality of second longitudinal grooves extending over the second outer conical region and the cylinder region. The number of the plurality of first longitudinal grooves is identical to the number of the plurality of second longitudinal grooves. The second longitudinal grooves are different from the first longitudinal grooves and differ in that the second longitudinal grooves are restricted to the second outer conical region and to the cylinder region and do not extend over the first outer conical region and the groove region.

The tool fitting is constructed in three parts from a basic body, an intermediate element and a locking device. The locking device is adjustable parallel to a longitudinal axis of the tool fitting between a receiving position and a locking position, wherein the shank is insertable into the tool fitting in the receiving position and is connected to the tool fitting in the locking position.

The intermediate element is annular designed with an inner driver region, which has a plurality of first inner rotary drivers with a first width and first depth and a plurality of second inner rotary drivers with a second width and second depth, and with an outer driver region, which has a plurality of first outer rotary drivers with a third width and third depth. The number of the plurality of first inner rotary drivers, the number of the plurality of second inner rotary drivers and the number of the plurality of first outer rotary drivers correspond. The basic body is sleeve-shaped with an inner conical region and a rotary driving region, which has a plurality of first outer rotary driving grooves.

In the connected state of the tool fitting and the shank, the first inner rotary drivers of the intermediate element engage in the first longitudinal grooves of the shank, the second inner rotary drivers of the intermediate element engage in the second longitudinal grooves of the shank, and the first outer rotary drivers of the intermediate element engage in the first outer rotary driving grooves. The torque, which is produced by a drill motor of the drill, is transmitted to the shank by means of the first and second inner rotary drivers.

The device for transmitting torque that is known from EP 1 211 005 B1 has the disadvantage that the tool fitting and the shank are approved only for drills having outputs of up to approx. 2.5 kW. At higher outputs, the surface pressure is very high, which can damage the inner and outer rotary drivers of the tool fitting. In addition, the service life of the tool fitting and of the shank is reduced.

The object of the present invention is to further develop the tool fitting and the shank of the device for transmitting torque that is known from EP 1 211 005 B1 such that the new device can transmit higher torques than the old device, the new shank can be connected to the old tool fitting and the new tool fitting cannot be connected to the old shank.

According to the invention, it is provided that the first depth of the first inner rotary drivers and the second depth of the second inner rotary drivers are identical, and the second longitudinal grooves of the shank also extend over the first outer conical region and the groove region. Owing to the fact that, in the case of the new tool fitting, the second depth of the second inner rotary drivers is identical to the first depth of the first inner rotary drivers, the second inner rotary drivers in the case of the new tool fitting have a greater second depth than in the case of the old tool fitting. The greater second depth of the second inner rotary drivers increases the contact area between the new tool fitting and the new shank and enables higher torques to be transmitted from the drill to the drill bit.

The greater second depth of the second inner rotary drivers prevents the new tool fitting, which is designed for powerful drills, from being able to be connected to the old shank, which is approved only for drills with outputs of up to approx. 2.5 kW, and thus increases the operational safety of the drill. Since the second longitudinal grooves of the old shank extend only over the second outer conical region and have a small depth, the second inner rotary drivers of the new tool fitting are too deep and cannot be inserted into the second longitudinal grooves of the old shank.

The second longitudinal grooves, which in the case of the new shank extend over the first outer conical region, the groove region and the second outer conical region, have a greater depth than the second longitudinal grooves of the old shank. This means that the new shank can be connected to the old tool fitting. The second inner rotary drivers of the old intermediate element engage in the second longitudinal grooves of the new shank. The new shank is designed for powerful drills and approved for greater forces and torques than the old tool fitting, which is not critical in operation. Operating a shank with outputs or torques that are lower than the permitted maximum value can have a positive effect on the service life of the shank.

The first width of the first inner rotary drivers and the second width of the second inner rotary drivers are preferably identical. The same depth and the same width of the first and second inner rotary drivers has the advantage that there is no need to assign the first inner rotary drivers to the first longitudinal grooves or the second inner rotary drivers to the second longitudinal grooves. Each inner rotary driver can be inserted into any longitudinal groove.

Preferably, the intermediate element has a plurality of second outer rotary drivers with a fourth width and fourth depth and the rotary driving region has a plurality of second outer rotary driving grooves, wherein, in the connected state of the device, the second outer rotary drivers engage in the second outer rotary driving grooves. The second outer rotary drivers increase the contact area between the basic body and the intermediate element and thereby enable the transmission of greater forces and torques. The larger the contact area, the lower the surface pressure between the basic body and the intermediate element, or if the surface pressure remains the same, greater forces and torques can be transmitted over the larger contact area.

Particularly preferably, the second outer rotary drivers are aligned with the second inner rotary drivers of the intermediate element in a plane perpendicular to the longitudinal axis of the tool fitting. The second outer rotary drivers increase the contact area between the basic body and the intermediate element and, if the surface pressure remains the same, thereby enable the transmission of greater forces and torques. Owing to the fact that the second outer rotary drivers are aligned with the second inner rotary drivers of the intermediate element, the force is transmitted from the tool fitting to the shank over the shortest path. The force or the torque is transmitted from the outer rotary driving grooves in the rotary driving region of the basic body to the outer rotary drivers of the intermediate element and is transmitted by the inner rotary drivers of the intermediate element to the longitudinal grooves of the shank.

The third depth of the first outer rotary drivers and the fourth depth of the second outer rotary drivers are preferably identical. The same depth and the same width of the first and second outer rotary drivers has the advantage that the force or the torque can be transmitted uniformly via the first and second outer rotary drivers from the basic body to the intermediate element.

The third depth of the first outer rotary drivers and the fourth depth of the second outer rotary drivers are particularly preferably identical. The same depth and the same width of the first and second outer rotary drivers has the advantage that the force or the torque can be transmitted uniformly via the first and second outer rotary drivers from the basic body to the intermediate element. In addition, there is no need to assign the first outer rotary drivers to the first outer rotary driving grooves or the second outer rotary drivers to the second outer rotary driving grooves. Each outer rotary driver can be inserted into any outer rotary driving groove.

In a preferred variant, the intermediate element is annular designed with an inner lateral surface, an outer lateral surface and a base surface, wherein a plurality of lower rotary drivers are arranged on the base surface of the intermediate element and a plurality of lower rotary driving grooves are arranged in an annular shoulder of the basic body, wherein, in the connected state of the tool fitting, the lower rotary drivers interact with the lower rotary driving grooves. The lower rotary drivers, which interact with the rotary driving grooves of the annular shoulder, increase the contact area between the basic body and the intermediate element without increasing the height of the rotary driving region and, if the contact pressure remains the same, thus enable the transmission of greater forces and torques.

The arrangement of the lower rotary drivers in the base surface of the intermediate element has the advantage that the loads on the intermediate element are better distributed, which can lead to a longer service life of the intermediate element. The forces that are transmitted from the first and second lower rotary drivers to the first and second inner rotary drivers run predominantly parallel to the longitudinal axis of the tool fitting, whereas the forces that are transmitted from the first and second outer rotary drivers to the first and second inner rotary drivers run predominantly in a plane perpendicular to the longitudinal axis of the tool fitting.

Preferably, the lower rotary drivers comprise a plurality of first lower rotary drivers with a fifth width and fifth depth and the lower rotary driving grooves comprise a plurality of first lower rotary driving grooves, wherein, in the connected state of the device, the first lower rotary drivers interact with the first lower rotary driving grooves. The formation of the first lower rotary drivers and the arrangement thereof on the base surface of the intermediate element has the advantage that the contact area between the basic body and the intermediate element is increased without increasing the height of the rotary driving region, and, in addition, the load on the intermediate element is shifted into other regions.

Particularly preferably, the first lower rotary drivers are aligned with the first inner rotary drivers of the intermediate element in a plane perpendicular to the longitudinal axis of the tool fitting. Owing to the fact that the first lower rotary drivers are aligned with the first inner rotary drivers, the force is transmitted over the shortest path from the tool fitting to the shank.

Preferably, the lower rotary drivers comprise a plurality of second lower rotary drivers with a sixth width and sixth depth and the lower rotary driving grooves comprise a plurality of second lower rotary driving grooves, wherein the second lower rotary drivers interact with the second lower rotary driving grooves. The formation of the second lower rotary drivers and the arrangement thereof on the base surface of the intermediate element has the advantage that the contact area between the basic body and the intermediate element is increased without increasing the height of the rotary driving region, and, in addition, the load on the intermediate element is shifted into other regions.

Particularly preferably, the second lower rotary drivers are aligned with the second inner rotary drivers of the intermediate element in a plane perpendicular to the longitudinal axis of the tool fitting. Owing to the fact that the second lower rotary drivers are aligned with the second inner rotary drivers, the force is transmitted over the shortest path from the tool fitting to the shank.

Particularly preferably, the fifth depth of the first lower rotary drivers and the sixth depth of the second lower rotary drivers are identical. The same depth of the first and second lower rotary drivers has the advantage that the force or the torque is transmitted uniformly via the first and second lower rotary drivers from the basic body to the intermediate element.

Particularly preferably, the fifth depth of the first lower rotary drivers and the sixth depth of the second lower rotary drivers are identical. The same depth and the same width of the first and second lower rotary drivers has the advantage that the force or the torque can be transmitted uniformly via the first and second lower rotary drivers from the basic body to the intermediate element. In addition, there is no need to assign the first lower rotary drivers to the first lower rotary driving grooves or the second lower rotary drivers to the second lower rotary driving grooves.

Exemplary embodiments of the invention are described hereinafter with reference to the drawings. It is not necessarily intended for this to illustrate the exemplary embodiments to scale; rather, the drawings are produced in a schematic and/or slightly distorted form where this is useful for explanation purposes. It should be taken into account here that various modifications and alterations relating to the form and detail of an embodiment may be undertaken without departing from the general concept of the invention. The general concept of the invention is not limited to the exact form or the detail of the preferred embodiment shown and described hereinafter or limited to subject matter that would be limited compared to the subject matter claimed in the claims. For given dimensioning ranges, values within the stated limits should also be disclosed as limit values and should be able to be used and claimed as desired. For the sake of simplicity, identical reference signs are used hereinafter for identical or similar parts or parts having identical or similar functions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a device according to the invention for transmitting torque from a drill to a drill bit, consisting of a tool fitting, which is connected to the drill, and a shank, which is connected to the drill bit;

FIGS. 2A, 2B show the tool fitting (FIG. 2A) and the shank (FIG. 2B) of the device according to the invention for transmitting torque that is illustrated in FIG. 1 ;

FIGS. 3A, 3B show the shank of the device according to the invention for transmitting torque in a side view (FIG. 3A) and in a longitudinal section along the section plane A-A in FIG. 3A (FIG. 3B);

FIGS. 4A, 4B show the device according to the invention for transmitting torque of FIG. 1 in the connected state in which the shank of FIG. 2B is connected to the tool fitting of FIG. 2A, in a side view (FIG. 4A) and in a longitudinal section along the section plane A-A in FIG. 4A (FIG. 4B);

FIGS. 5A-C show a basic body of the tool fitting in a side view (FIG. 5A), in a longitudinal section along the section plane A-A in FIG. 5A (FIG. 5B) and in a plan view of the interface with an intermediate element of the tool fitting (FIG. 5C); and

FIGS. 6A-C show an intermediate element of the tool fitting in a side view (FIG. 6A), in a longitudinal section along the section plane A-A in FIG. 6A (FIG. 6B) and in a plan view of the interface with the basic body (FIG. 6C).

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a device 10 according to the invention for transmitting a torque from a drill 11 to a drill bit 12. The device 10 is arranged between the drill 11 and the drill bit 12 and transmits the torque from the drill 11 to the drill bit 12.

The device 10 is constructed from a tool fitting 13, which is connected to the drill 11, and a shank 14, which is connected to the drill bit 12. The device 10 is connected to the drill 11 via a first connection 15 and to the drill bit 12 via a second connection 16. In the connected state of the device 10, torque is transmitted via the following components: drive shaft 17 of the drill 11, tool fitting 13, shank 14 and drill bit 12. The connected state of the device 10 is defined as the state in which the tool fitting 13 and the shank 14 are connected.

FIGS. 2A, 2B show the drill 11 with the tool fitting 13 (FIG. 2A) and the drill bit 12 with the shank 14 (FIG. 2B) of the device 10 according to the invention. The tool fitting 13 and the shank 14, in the connected state, form the device 10 according to the invention of FIG. 1 .

The tool fitting 13 is connected to the drill 11 via the first connection 15, which in the exemplary embodiment is designed as a releasable connection; alternatively, the tool fitting 13 can be connected to the drill 11 via a non-releasable first connection 15. Since the tool fitting 13 is a wearing part, it makes sense to design the tool fitting 13 as a separate component and to connect it to the drive shaft 17 of the drill 11 via a releasable first connection. In order to ensure that the drill 11 is operated only with an approved tool fitting 13, it makes sense to design the first connection 15 in such a way that it can be operated only with a special tool.

The shank 14 is connected to the drill bit 12 via the second connection 16, which is designed as a releasable connection in the exemplary embodiment. For this purpose, the drill bit 12 has an internal thread which is connected to an external thread of the shank 14. The releasable second connection 16 is designed, for example, as a metric ISO threaded connection or other releasable connection. Instead of the releasable second connection 16, the shank 14 can be connected non-releasably to the drill bit 12; for this purpose, the shank 14 can be connected non-releasably to the drill bit 12, for example by welding or other methods.

The drive shaft 17 is designed to be rotatable about a first axis of rotation 21 which, in the connected state of the tool fitting 13 and the drill 11, coincides with a longitudinal axis 22 of the tool fitting 13. The drill bit 12 is designed to be rotatable during operation about a second axis of rotation 23 which, in the connected state of the shank 14 and the drill bit 12, coincides with a longitudinal axis 24 of the shank 14. For differentiation purposes, the longitudinal axis 22 of the tool fitting 13 is referred to as the first longitudinal axis 22 and the longitudinal axis 24 of the shank 14 is referred to as the second longitudinal axis 24. In the connected state of the drill 11 and the drill bit 12, the first longitudinal axis 22 and second longitudinal axis 24 are arranged coaxially to one another.

FIGS. 3A, 3B show the shank 14 of the device 10 according to the invention for transmitting torque in the non-connected state of the device 10 in a side view (FIG. 3A) and in a longitudinal section along the section plane A-A in FIG. 3A (FIG. 3B). The shank 14 is constructed from a first portion 26 and a second portion 27, which in the exemplary embodiment are formed in one piece and have a central through-hole 28.

The second portion 27 of the shank 14 has an external thread 29, forming the second threaded connection 16 with a matching internal thread of the drill bit 12. The first portion 26 of the shank 14 is composed of five portions and includes a front region 32, a first outer conical region 33, a groove region 34, a second outer conical region 35 and a cylinder region 36. The first and second outer conical region 33, 35 have a first or second conical outer surface which widens in the direction of the drill bit 12. The conical outer surfaces are produced for example by turning; by manufacturing the first and second conical outer surface in one setting, high manufacturing accuracy can be achieved.

The shank 14 has a plurality of first longitudinal grooves 37 and a plurality of second longitudinal grooves 38, which extend parallel to the second longitudinal axis 24 of the shank 14 and are arranged on the outside of the first portion 26. The first longitudinal grooves 37 and second longitudinal grooves 38 are identically formed in the exemplary embodiment and extend over the first outer conical region 33, the groove region 34 and the second outer conical region 35 and also over the cylinder region 36. The first longitudinal grooves 37 and second longitudinal grooves 38 are uniformly distributed in the circumferential direction 39 of the shank 14 and are arranged alternately, each first longitudinal groove 37 being arranged between two second longitudinal grooves 38. In the exemplary embodiment, the shank 14 has three first longitudinal grooves 37 and three second longitudinal grooves 38; it generally applies that the number of the plurality of first longitudinal grooves 37 is identical to the number of the plurality of second longitudinal grooves 38.

FIGS. 4A, 4B show the device 10 according to the invention for transmitting torque in the connected state, in which the shank 14 is connected to the tool fitting 13, in a side view (FIG. 4A) and in a longitudinal section along the section plane A-A in FIG. 4A (FIG. 4B).

The tool fitting 13 is constructed from a basic body 41, an intermediate element 42 and a locking device 43. The intermediate element 42 forms the interface between the tool fitting 13 and the shank 14 and the torque is transmitted from the intermediate element 42 to the shank 14. The connected state of the tool fitting 13 is defined as the state in which the basic body 41, the intermediate element 42 and the locking device 43 are connected.

The locking device 43 is designed to be adjustable relative to the basic body 41, wherein the locking device 43 is displaceable in a longitudinal direction 44 that runs parallel to the first longitudinal axis 22 of the tool fitting 13, and is rotatable about the first longitudinal axis 22. The locking device 43 is adjustable between a plurality of positions, which are referred to as the basic position, receiving position and locking position. In order to be able to connect the shank 14 to the tool fitting 13 in a form-fitting manner, the locking device 43 is shifted from the basic position in the longitudinal direction 44 into the receiving position. In the receiving position, the shank 14 is inserted into the tool fitting 13. To lock the device 10, the locking device 43 is rotated about the first longitudinal axis 22 into the locking position. In the process, locking elements 45 engage in the groove region 34 of the shank 14 and lock the shank 14 to the tool fitting 13. The basic position of the locking device 43 is optional and can be omitted; the receiving position and locking position of the locking device 43 are necessary.

FIGS. 5A-C show the basic body 41 of the tool fitting 13 in a side view (FIG. 5A), in a longitudinal section along the section plane A-A in FIG. 5A (FIG. 5B) and in a plan view of the interface with the intermediate element 42 (FIG. 5C).

The basic body 41 is sleeve-shaped with a central through-hole 47 and is composed of a plurality of portions, which in the exemplary embodiment are made in one piece. In addition to the internal thread, the basic body 41 comprises an internal conical region 48 which interacts with the shank 14, and a rotary driving region 49, which interacts with the intermediate element 42. The inner conical region 48 has a conical inner surface which widens in the direction of the drill. In the connected state of the device 10, the inner conical region 48 of the basic body 41 and the first and second outer conical region 33, 35 of the shank 14 form a form-fitting connection.

The rotary driving region 49 is formed in a step-shaped manner from an annular collar 51 and an annular shoulder 52. A plurality of first outer rotary driving grooves 53 and a plurality of second outer rotary driving grooves 54 are provided in the annular collar 51, said grooves interacting with first outer rotary drivers and second outer rotary drivers of the intermediate element 42 in the connected state of the tool fitting 13, and a plurality of first lower rotary driving grooves 55 and a plurality of second lower rotary driving grooves 56 are provided in the annular shoulder 51, said grooves interacting with first and second lower rotary drivers of the intermediate element 42 in the connected state of the device 10. The first and second outer rotary driving grooves 53, 54 are combined under the term “outer rotary driving grooves” and the first and second lower rotary driving grooves 55, 56 are combined under the term “lower rotary driving grooves”.

The first outer rotary driving grooves 54 and second outer rotary driving grooves 55 are uniformly distributed in a circumferential direction 57 of the shank 41 in the annular collar 51 of the rotary driving region 49 and are arranged alternately, each first outer rotary driving groove 55 being arranged between two second outer rotary driving grooves 56. The first lower rotary driving grooves 56 and second lower rotary driving grooves 57 are uniformly distributed in the circumferential direction 57 of the basic body 41 in the annular shoulder 52 and are arranged alternately, each first lower rotary driving groove 55 being arranged between two second lower rotary driving grooves 56.

In the exemplary embodiment, the annular collar 51 has three first outer rotary driving grooves 53 and three second outer rotary driving grooves 54 and the annular shoulder 52 has three first lower rotary driving grooves 55 and three second lower rotary driving grooves 56; it applies in general that the number of the plurality of first outer rotary driving grooves 53 is identical to the number of the plurality of second outer rotary driving grooves 54, and the number of the plurality of first lower rotary driving grooves 55 is identical to the number of the plurality of second lower rotary driving grooves 56.

FIGS. 6A-C show the intermediate element 42 of the tool fitting 13 in a side view (FIG. 6A), in a longitudinal section along the section plane A-A in FIG. 6A (FIG. 6B) and in a plan view of the interface with the basic body 41 (FIG. 6C). In the connected state of the device 10, the intermediate element 42 is arranged between the basic body 41 and the shank 14 and the torque is transmitted from the basic body 41 via the intermediate element 42 to the shank 14.

The intermediate element 42 is annular designed with a base surface 61, an inner lateral surface 62 and an outer lateral surface 63. The inner lateral surface 62 forms an inner driver region and the outer lateral surface 63 forms an outer driver region. On the inner lateral surface 62, the intermediate element 42 has a plurality of first inner rotary drivers 64 and a plurality of second inner rotary drivers 65 which, in the connected state of the device 10, engage in the first longitudinal grooves 37 and second longitudinal grooves 38 of the shank 14. On the outer lateral surface 63, the intermediate element 42 has a plurality of first outer rotary drivers 66 and a plurality of second outer rotary drivers 67 which, in the connected state of the tool fitting 13, engage in the first outer rotary driving grooves 53 and second outer rotary driving grooves 54 on the annular collar 51 of the basic body 41.

The first inner rotary drivers 64 and second inner rotary drivers 65 are combined under the term “inner rotary driver”. Perpendicular to the first longitudinal axis 22 of the tool fitting 13, the first inner rotary drivers 64 have a first width B₁ and a first depth T₁ and the second inner rotary drivers 65 have a second width B₂ and a second depth T₂. Parallel to the first longitudinal axis 22 of the tool fitting 13, the first inner rotary drivers 64 extend over a first height H₁ and the second inner rotary drivers 65 extend over a second height H₂. In order to set the surface pressure between the intermediate element 42 and the shank 14 to be as small as possible, the first height H₁ and the second height H₂ are as large as possible.

The first and second outer rotary drivers 66, 67 are combined under the term “outer rotary drivers”. Perpendicular to the first longitudinal axis 22 of the tool fitting 13, the first outer rotary drivers 66 have a third width B₃ and a third depth T₃ and the second outer rotary drivers 67 have a fourth width B₄ and a fourth depth T₄. Parallel to the first longitudinal axis 22 of the tool fitting 13, the first outer rotary drivers 66 have a third height H₃ and the second outer rotary drivers 67 have a fourth height H₄. In order to set the surface pressure between the basic body 41 and the intermediate element 42 to be as small as possible, the third height H₃ and the fourth height H₄ are as large as possible.

The first outer rotary drivers 66 and second outer rotary drivers 67 are aligned in a plane 68 perpendicular to the first longitudinal axis 22 of the tool fitting 13 with the first inner rotary drivers 64 and second inner rotary drivers 65, respectively. This arrangement has the advantage that the forces are transmitted directly from the basic body 41 to the shank 14. In the connected state of the device 10, the force flows onto the first outer rotary drivers 66 and second outer rotary drivers 67 on the outer lateral surface 63 of the intermediate element 42; the forces are transmitted via the intermediate element 42 to the first inner rotary drivers 64 and second inner rotary drivers 65 on the inner lateral surface 62 of the intermediate element 42, the first inner rotary drivers 64 transmitting the forces to the first longitudinal grooves 37 and the second inner rotary drivers 65 transmitting the forces to the second longitudinal grooves 38.

In addition to the inner rotary drivers 64, 65 and outer rotary drivers 66, 67, the intermediate element 42 has a plurality of first lower rotary drivers 71 and a plurality of second lower rotary drivers 72, which are arranged on the base surface 61 of the intermediate element 42 and which merge into the first inner rotary drivers 64 and the second inner rotary drivers 65, respectively. The first lower rotary drivers 71 merge into the first inner rotary drivers 64 and the second lower rotary drivers 72 merge into the second inner rotary drivers 65.

The first and second lower rotary drivers 71, 72 are combined under the term “lower rotary drivers”. Perpendicular to the first longitudinal axis 22 of the tool fitting 13, the first lower rotary drivers 71 have a fifth width B₅ and a fifth depth T₅ and the second lower rotary drivers 72 have a sixth width B₆ and a sixth depth T₆. Parallel to the first longitudinal axis 22 of the tool fitting 13, the first lower rotary drivers 71 have a fifth height H₅ and the second lower rotary drivers 72 have a sixth height H₆. In order to set the surface pressure between the basic body 41 and the intermediate element 42 to be as small as possible, the fifth height H₅ and sixth height H₆ are as large as possible.

The intermediate element 42 illustrated in the exemplary embodiment has all the rotary drivers which are designed as first and second inner rotary drivers 64, 65, as first and second outer rotary drivers 66, 67 and as first and second lower rotary drivers 71, 72. The second outer rotary drivers 67 and the first and second lower rotary drivers 71, 72 are optional. The contact area between the basic body 41 and the intermediate element 42 is increased by the second outer rotary drivers 67, first lower rotary drivers 71 and second lower rotary drivers 72.

In the new tool fitting 13, the first depth T₁ of the first inner rotary drivers 64 is identical to the second depth T₂ of the second inner rotary drivers 65. With the old tool fitting, the second depth of the second inner rotary drivers is smaller than the first depth of the first inner rotary drivers. The greater second depth of the second inner rotary drivers increases the contact area between the new tool fitting and the new shank and enables greater forces and torques to be transmitted from the drill to the drill bit. The same depth (T₁=T₂) of the first inner rotary drivers 64 and second inner rotary drivers 65 also has the advantage that the new tool fitting cannot be combined with the old shank, since the dimensions of the second longitudinal grooves 38 in the plane perpendicular to the second longitudinal axis 24 of the shank 14 are too small to be combined with the second inner rotary drivers 65.

In the exemplary embodiment of the device 10, the first width B₁ of the first inner rotary drivers 64 is identical to the second width B₂ of the second inner rotary drivers 65. With the old tool fitting, the second width of the second inner rotary drivers is smaller than with the new tool fitting. The same depth (T₁=T₂) and the same width (B₁=B₂) of the first inner rotary drivers 64 and second inner rotary drivers 65 has the advantage that there is no need to assign the first inner rotary drivers 64 to the first longitudinal grooves 37 or the second inner rotary drivers 65 to the second longitudinal grooves 38.

The new tool fitting 13 illustrated in the exemplary embodiment differs from the old tool fitting in that it has the second outer rotary drivers 67 and second outer rotary driving grooves 54. In the connected state of the device 10, the second outer rotary drivers 67 engage in the second outer rotary driving grooves 54 of the basic body 41. The second outer rotary drivers 67 and rotary driving grooves 54 increase the contact area between the basic body 41 and the intermediate element 42 and thereby enable the transmission of greater forces and torques. The larger the contact area, the lower the surface pressure between the basic body 41 and the intermediate element 42, or if the surface pressure remains the same, greater forces and torques can be transmitted over the larger contact area.

In the exemplary embodiment of the device 10, the third depth T₃ of the first outer rotary drivers 66 is identical to the fourth depth T₄ of the second outer rotary drivers 67. The same depth (T₃=T₄) of the first outer rotary drivers 66 and second outer rotary drivers 67 has the advantage that the force or torque is transmitted uniformly via the first and second outer rotary drivers 66, 67 from the basic body 41 to the intermediate element 42. In addition, in the exemplary embodiment of the device 10, the third width of the first outer rotary drivers 66 and the fourth width of the second outer rotary drivers 67 are identical. The same depth (T₃=T₄) and the same width (B₃=B₄) of the first outer rotary drivers 66 and second outer rotary drivers 67 has the advantage that there is no need to assign the first outer rotary drivers 66 to the first outer rotary driving grooves 53 or the second outer rotary drivers 67 to the second outer rotary driving grooves 54. Each outer rotary driver can be inserted into any outer rotary driving groove.

The new tool fitting 13 illustrated in the exemplary embodiment differs from the old tool fitting in that it has the lower rotary drivers 71, 72 and lower rotary driving grooves 55, 56. The design of the first lower rotary drivers 71 and second lower rotary drivers 72 and the arrangement thereof on the base surface 61 of the intermediate element 42 has the advantage that the contact area between the basic body 41 and the intermediate element 42 is increased without increasing the height of the rotary driving region 49. In addition, the load on the intermediate element 42 is shifted into other regions. The force flow that arises during the transmission of force from the first outer rotary drivers 66 and second outer rotary drivers 67 to the first inner rotary drivers 64 or second inner rotary drivers 65 runs predominantly in the plane 68 perpendicular to the first longitudinal axis 22 of the tool fitting 13, and the force flow that arises during the transmission of force from the first lower rotary drivers 71 and second lower rotary drivers 72 to the first inner rotary drivers 64 and second inner rotary drivers 65, respectively, runs predominantly parallel to the first longitudinal axis 22 of the tool fitting 13. The loads on the intermediate element 42 are better distributed, which leads to a longer service life of the intermediate element 42.

In the exemplary embodiment of the device 10, the fifth depth T₅ of the first lower rotary drivers 71 is identical to the sixth depth T₆ of the second lower rotary drivers 72. The same depth (T₅=T₆) of the first lower rotary drivers 71 and second lower rotary drivers 72 has the advantage that the force or the torque is transmitted uniformly via the first lower rotary drivers 71 and second lower rotary drivers 72 from the basic body 41 to the intermediate element 42. In addition, in the exemplary embodiment of the device 10, the fifth width B₅ of the first lower rotary drivers 71 is identical to the sixth width B₆ of the second lower rotary drivers 72. The same depth (T₅=T₆) and the same width (B₅=B₆) of the first lower rotary drivers 71 and second lower rotary drivers 72 has the advantage that the force or torque can be distributed uniformly via the first lower rotary drivers 71 and the second lower rotary drivers 72 from the basic body 41 to the intermediate element 42 and, in addition, there is no need to assign the first lower rotary drivers 71 to the first lower rotary driving grooves 55 or the second lower rotary drivers 72 to the second lower rotary driving grooves 56. 

1.-13. (canceled)
 14. A device (10) for transmitting a torque produced by a drill (11), to a drill bit (12), comprising: a shank (14) having a first outer conical region (33), a groove region (34), and a second outer conical region (35) and having a plurality of first longitudinal grooves (37) extending over the first outer conical region (33), the groove region (34), and the second outer conical region (35) and having a plurality of second longitudinal grooves (38) extending over the second outer conical region (35), wherein a number of the plurality of first longitudinal grooves (37) is identical to a number of the plurality of second longitudinal grooves (38); and a tool fitting (13) which has a basic body (41), an intermediate element (42), and a locking device (43); wherein the intermediate element (42) has a plurality of first inner rotary drivers (64) with a first width (B₁) and a first depth (T₁), a plurality of second inner rotary drivers (65) with a second width (B₂) and a second depth (T₂), and a plurality of first outer rotary drivers (66) with a third width (B₃) and a third depth (T₃); wherein the basic body (41) has an inner conical region (48) and a rotary driving region (49) with a plurality of first outer rotary driving grooves (53) and wherein, in a connected state of the tool fitting (13), the first outer rotary drivers (66) of the intermediate element (42) engage in the first outer rotary driving grooves (53); wherein the locking device (43) is adjustable parallel to a longitudinal axis (22) of the tool fitting (13) between a receiving position and a locking position and wherein the shank (14) is insertable into the tool fitting (13) in the receiving position and is connected to the tool fitting (13) in the locking position; wherein, in a connected state of the device (10), the first inner rotary drivers (64) of the intermediate element (42) engage in the first longitudinal grooves (37) of the shank (14) and the second inner rotary drivers (65) of the intermediate element (42) engage in the second longitudinal grooves (38) of the shank (14); wherein the first depth (T₁) of the first inner rotary drivers (64) and the second depth (T₂) of the second inner rotary drivers (65) are identical and wherein the second longitudinal grooves (38) of the shank (14) also extend over the first outer conical region (33) and the groove region (34).
 15. The device (10) as claimed in claim 14, wherein the first width (B₁) of the first inner rotary drivers (64) and the second width (B₂) of the second inner rotary drivers (65) are identical.
 16. The device (10) as claimed in claim 14, wherein the intermediate element (42) has a plurality of second outer rotary drivers (67) with a fourth width (B₄) and a fourth depth (T₄), wherein the rotary driving region (49) has a plurality of second outer rotary driving grooves (54), and wherein, in the connected state of the device (10), the second outer rotary drivers (67) engage in the second outer rotary driving grooves (54).
 17. The device (10) as claimed in claim 16, wherein the second outer rotary drivers (67) are aligned with the second inner rotary drivers (65) of the intermediate element (42) in a plane (68) perpendicular to the longitudinal axis (22) of the tool fitting (13).
 18. The device (10) as claimed in claim 16, wherein the third depth (T₃) of the first outer rotary drivers (66) and the fourth depth (T₄) of the second outer rotary drivers (67) are identical.
 19. The device (10) as claimed in claim 18, wherein the third width (B₃) of the first outer rotary drivers (66) and the fourth width (B₄) of the second outer rotary drivers (67) are identical.
 20. The device (10) as claimed in claim 14, wherein the intermediate element (42) is annular designed with an inner lateral surface (62), an outer lateral surface (63), and a base surface (61), wherein a plurality of lower rotary drivers (71, 72) are arranged on the base surface (61) of the intermediate element (42) and a plurality of lower rotary driving grooves (55, 56) are arranged in an annular shoulder (52) of the rotary driving region (49), and wherein, in the connected state of the device (10), the lower rotary drivers (71, 72) interact with the lower rotary driving grooves (55, 56).
 21. The device (10) as claimed in claim 20, wherein the lower rotary drivers (71, 72) comprise a plurality of first lower rotary drivers (71) with a fifth width (B₅) and a fifth depth (T₅) and the lower rotary driving grooves (55, 56) comprise a plurality of first lower rotary driving grooves (55) and wherein, in the connected state of the device (10), the first lower rotary drivers (71) interact with the first lower rotary driving grooves (55).
 22. The device (10) as claimed in claim 21, wherein the first lower rotary drivers (71) are aligned with the first inner rotary drivers (64) of the intermediate element (42) in a plane (68) perpendicular to the longitudinal axis (22) of the tool fitting (13).
 23. The device (10) as claimed in claim 21, wherein the lower rotary drivers (71, 72) comprise a plurality of second lower rotary drivers (72) with a sixth width (B₆) and a sixth depth (T₆) and the lower rotary driving grooves (55, 56) comprise a plurality of second lower rotary driving grooves (56) and wherein, in the connected state of the device (10), the second lower rotary drivers (72) interact with the second lower rotary driving grooves (56).
 24. The device (10) as claimed in claim 23, wherein the second lower rotary drivers (72) are aligned with the second inner rotary drivers (65) of the intermediate element (42) in a plane (68) perpendicular to the longitudinal axis (22) of the tool fitting (13).
 25. The device (10) as claimed in claim 23, wherein the fifth depth (T₅) of the first lower rotary drivers (71) and the sixth depth (T₆) of the second lower rotary drivers (72) are identical.
 26. The device (10) as claimed in claim 25, wherein the fifth width (B₅) of the first lower rotary drivers (71) and the sixth width (B₆) of the second lower rotary drivers (72) are identical. 